Lifting walls in tube mills are intended to separate the grinding body fillings of adjacent grinding chambers from each other, and to convey from one chamber to the other the material being ground.
In order to optimise the grinding process it is important for the time spent by the material in the individual chambers to be matched as precisely as possible to the prevailing conditions. With known constructions the time spent in each of the chambers by the material being ground, and hence the value of the output or operating rate is in general varied by appropriate choice of slot width in the slotted plates mounted on one support plate of the lifting wall.
A disadvantage of these known constructions is that the time spent and hence the output when once selected can only be altered by major conversions of the lifting wall, for example by installing different slotted plates or covering over individual slotted plates.